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Antenna-Theory.com Presents the Spiral Antenna
Antenna-Theory.com Presents the Spiral Antenna
Published: 2011/07/17
Channel: Pete's Free Info Center
design Archimedean spiral antenna connected to coax
design Archimedean spiral antenna connected to coax
Published: 2017/02/03
Channel: Ahmed assad
Spiral antenna
Spiral antenna
Published: 2012/05/23
Channel: ChipDipvideo
K6ZRH- TAK-tenna antenna demo (20M shortest HF dipole spiral antenna)
K6ZRH- TAK-tenna antenna demo (20M shortest HF dipole spiral antenna)
Published: 2009/08/25
Channel: dandyradio
Wideband Spiral  Helical Cone Antenna for WiFi and FPV
Wideband Spiral Helical Cone Antenna for WiFi and FPV
Published: 2015/10/29
Channel: andrew mcneil
SOLIDWORKS - Conical Log Spiral Antenna
SOLIDWORKS - Conical Log Spiral Antenna
Published: 2017/07/21
Channel: GoEngineer
KingKong 90GT - Linear vs Spiral antenna
KingKong 90GT - Linear vs Spiral antenna
Published: 2017/08/18
Channel: firebird123
Cavity backed log spiral antenna
Cavity backed log spiral antenna
Published: 2013/03/11
Channel: antennamagus
Short Spiral Antenna
Short Spiral Antenna
Published: 2016/06/23
Channel: BigBikeParts
Spiral Antenna Video 3
Spiral Antenna Video 3
Published: 2012/03/28
Channel: Vampyricintentions
11 Frequency Independent Antennas, Antenna Miniaturization, and Fractal Antennas
11 Frequency Independent Antennas, Antenna Miniaturization, and Fractal Antennas
Published: 2016/07/04
Channel: Castor Classes
Antenna-Theory.com Presents the Spiral Antenna - YouTube.flv
Antenna-Theory.com Presents the Spiral Antenna - YouTube.flv
Published: 2012/03/20
Channel: scriptumclarum
Kupferschnecke Kurzwelle 3.5 - 16 Mhz Copper Spiral Antenna
Kupferschnecke Kurzwelle 3.5 - 16 Mhz Copper Spiral Antenna
Published: 2015/10/03
Channel: Wanderlinse
5 8GHz Spiral Helical Cone Antenna
5 8GHz Spiral Helical Cone Antenna
Published: 2015/11/14
Channel: andrew mcneil
AM Spiral Loop Antenna
AM Spiral Loop Antenna
Published: 2010/03/16
Channel: Jim Whitaker
Spiral Theory
Spiral Theory
Published: 2007/08/16
Channel: Sam Flynn
The First in a Range of High Power Spiral Antennas from Cobham Antenna Systems
The First in a Range of High Power Spiral Antennas from Cobham Antenna Systems
Published: 2016/04/15
Channel: Cobham plc
Ham Radio - Building a spiral loop antenna for 20 meters
Ham Radio - Building a spiral loop antenna for 20 meters
Published: 2017/09/24
Channel: Kevin Loughin
spiralantenna For FM Log Spiral Antenna Draft vesion can be bettered more
spiralantenna For FM Log Spiral Antenna Draft vesion can be bettered more
Published: 2016/02/12
Channel: li woo
Deployable Spiral - IEEE APS 2017 Student Design Contest for CubeSat Antenna by Missouri S&T team
Deployable Spiral - IEEE APS 2017 Student Design Contest for CubeSat Antenna by Missouri S&T team
Published: 2017/04/29
Channel: Ali Foudazi
HF Spiral Loop build video 1
HF Spiral Loop build video 1
Published: 2012/03/26
Channel: Vampyricintentions
RX comparison on AM broadcast band between 40m dipole and my new large spiral antenna
RX comparison on AM broadcast band between 40m dipole and my new large spiral antenna
Published: 2016/08/10
Channel: Epoch Xenomania
Kingkong 90GT with spiral antenna
Kingkong 90GT with spiral antenna
Published: 2017/08/19
Channel: firebird123
Curved Spiral Antennas for Freshwater Applications
Curved Spiral Antennas for Freshwater Applications
Published: 2015/01/20
Channel: Underwaterteam Uiowa
Deploy-Anywhere Vertical HF Antenna
Deploy-Anywhere Vertical HF Antenna
Published: 2015/09/30
Channel: QRP School
Two 5.8GHz FPV helical antennas compared
Two 5.8GHz FPV helical antennas compared
Published: 2014/02/06
Channel: RCModelReviews
80m indoor spiral loop
80m indoor spiral loop
Published: 2017/03/01
Channel: alaindecarolis
Kc boro marble spiral antenna pink swirls
Kc boro marble spiral antenna pink swirls
Published: 2010/12/21
Channel: marblemaker117
how to draw/construct an Archimedean Spiral [HINDI]
how to draw/construct an Archimedean Spiral [HINDI]
Published: 2017/01/27
Channel: Vikash Academy
6/02/2014 -- Spiral Vortex RADAR pulse in Australia - covering Exmouth Antenna Array
6/02/2014 -- Spiral Vortex RADAR pulse in Australia - covering Exmouth Antenna Array
Published: 2014/06/02
Channel: dutchsinse
HF Spiral Loop Antenna video 2.
HF Spiral Loop Antenna video 2.
Published: 2012/03/26
Channel: Vampyricintentions
Show Chrome Short Spiral AM/FM Antenna - 7 1/2" Replacement Antenna Review
Show Chrome Short Spiral AM/FM Antenna - 7 1/2" Replacement Antenna Review
Published: 2017/04/11
Channel: Kenny D's Garage
2 4GHz Single Turn Double Helical Antenna
2 4GHz Single Turn Double Helical Antenna
Published: 2015/02/27
Channel: andrew mcneil
MATLAB ARCHIMEDEAN SPIRAL DESIGN INVESTIGATION
MATLAB ARCHIMEDEAN SPIRAL DESIGN INVESTIGATION
Published: 2016/02/04
Channel: pgembeddedsystems matlabprojects
Exit Spiral
Exit Spiral
Published: 2016/12/03
Channel: Antenna Farm - Topic
G3XBM
G3XBM's 500kHz antenna (in snow)
Published: 2009/12/18
Channel: G3XBM
Helical Antenna
Helical Antenna
Published: 2014/01/07
Channel: GPUAPPS
Ham Radio - The simple coax cable emergency prepper antenna.
Ham Radio - The simple coax cable emergency prepper antenna.
Published: 2017/03/09
Channel: Kevin Loughin
Antenna and Propagation   Polarization Measurement (Lab 5 ME1300)
Antenna and Propagation Polarization Measurement (Lab 5 ME1300)
Published: 2014/08/01
Channel: KEYSIGHT EDUCATORS
Tutorial creacion antena helicoidad FEKO
Tutorial creacion antena helicoidad FEKO
Published: 2016/09/19
Channel: Diego F Calderon Silva
Spiral Aerial hop across central
Spiral Aerial hop across central
Published: 2016/04/27
Channel: kendrickmeadows
Ham Radio - 80 160 meter magnetic loop transmitting antenna
Ham Radio - 80 160 meter magnetic loop transmitting antenna
Published: 2015/05/10
Channel: Kevin Loughin
Infinite Spiral Longwire Antenna
Infinite Spiral Longwire Antenna
Published: 2015/03/07
Channel: Stan Gibilisco
TRP (Total Radiated Power) and Spiral Scan
TRP (Total Radiated Power) and Spiral Scan
Published: 2013/03/10
Channel: 2Chairs1Technology
HFSS 100 Tips +Plus #17.Equation Based Curve (Helix/Spiral 그리기)
HFSS 100 Tips +Plus #17.Equation Based Curve (Helix/Spiral 그리기)
Published: 2015/04/15
Channel: ANSYS KOREA Support
DL_FLIGHTLOG 39 (FPV DRONE)
DL_FLIGHTLOG 39 (FPV DRONE)
Published: 2017/11/13
Channel: Derrick Leong
DL_FLIGHTLOG 35 (FPV DRONE)
DL_FLIGHTLOG 35 (FPV DRONE)
Published: 2017/11/07
Channel: Derrick Leong
broadband antennas
broadband antennas
Published: 2013/04/01
Channel: cfurse
Ansys Maxwell - HFSS How to model helix circular coil for WPT
Ansys Maxwell - HFSS How to model helix circular coil for WPT
Published: 2014/11/03
Channel: kamyar K
DL_FLIGHTLOG 37 (FPV DRONE)
DL_FLIGHTLOG 37 (FPV DRONE)
Published: 2017/11/11
Channel: Derrick Leong
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WIKIPEDIA ARTICLE

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Two-arm log spiral antenna

In microwave systems, a spiral antenna is a type of RF antenna. It is shaped as a two-arm spiral, or more arms may be used.[1] Spiral antennas were first described in 1956.[2] Spiral antennas belong to the class of frequency independent antennas which operate over a wide range of frequencies. Polarization, radiation pattern and impedance of such antennas remain unchanged over large bandwidth.[3] Such antennas are inherently circularly polarized with low gain. Array of spiral antennas can be used to increase the gain. Spiral antennas are reduced size antennas with its windings making it an extremely small structure. Lossy cavities are usually placed at the back to eliminate back lobes because a unidirectional pattern is usually preferred in such antennas. Spiral antennas are classified into different types; archimedean spiral, square spiral and star spiral etc. Archimedean spiral is the most popular configuration.

Working[edit]

These antennas operate in 3 ways: traveling wave, fast wave, and leaky wave.

The traveling wave, formed on spiral arms, allows for broadband performance. Fast wave is due to mutual coupling phenomenon occurring between arms of spiral. Leaky wave “leaks” the energy during propagation through the spiral arms to produce radiation.

Ring theory (band theory) explains the working principle of spiral antenna. The theory states that spiral antenna radiates from an active region where the circumference of spiral equals the wavelength.[4]

Design[edit]

Different design parameters are to be considered while designing a square spiral antenna. The parameters include spacing between the turns , width of arm , inner radius and outer radius . The inner radius is measured from center of the spiral to center of the first turn while the outer radius is measured from center of the spiral to center of the outermost turn. Other than these design parameters, spiral antennas have lowest ( and highest operating frequencies. Here corresponds to speed of light. In an coordinate system, the spiral grows along the -axis and -axis simultaneously. All spirals satisfy equation where corresponds to growth factor and corresponds to multiplication factor.

Different designs of spiral antenna can be obtained by varying number of turns it contains, the spacing between its turns and the width of its arm. A dielectric medium is used with a specific permittivity and dimensions over which the spiral is printed. Dielectric mediums like Rogers RT Duroid help in reducing the physical size of antenna. Thin substrates with higher permittivity can achieve the same result as thick substrates with lower permittivity. The only problem with such materials is their less availability and high costs.[5]

Applications[edit]

A spiral antenna transmits EM waves having a circular polarization. It will receive linearly polarized EM waves in any orientation, but will attenuate signals received with the opposite circular polarization. A spiral antenna will reject circularly polarized waves of one type, while receiving perfectly well waves having the other polarization.

One application of spiral antennas is wideband communications. Another application of spiral antennas is monitoring of the frequency spectrum. One antenna can receive over a wide bandwidth, for example a ratio 5:1 between the maximum and minimum frequency. Usually a pair of spiral antennas are used in this application, having identical parameters except the polarization, which is opposite (one is right-hand, the other left-hand oriented). Spiral antennas are useful for microwave direction-finding.[6]

Elements[edit]

The antenna includes two conductive spirals or arms, extending from the center outwards. The antenna may be a flat disc, with conductors resembling a pair of loosely nested clock springs, or the spirals may extend in a three-dimensional shape like a screw thread. The direction of rotation of the spiral defines the direction of antenna polarization. Additional spirals may be included as well, to form a multi-spiral structure. Usually the spiral is cavity-backed, that is there is a cavity of air or non-conductive material or vacuum, surrounded by conductive walls; the cavity changes the antenna pattern to a unidirectional shape. The output of the antenna is a balanced line. If one input or output line is desired, for example a coaxial line, then a balun or other device is added to so transform the signals.

References[edit]

  1. ^ Richard C. Johnson, Henry Jasik, Antenna Engineering Handbook, Second Edition, ISBN 0-07-032291-0, 1961, Chapter 14-2
  2. ^ Orr, William I. (1976). Beam Antenna Handbook, 5th Edition. Radio Publications, Inc. pp. 185–186. 
  3. ^ Paul E. Mayes, “Frequency-Independent Antennas and Broad-Band Derivatives Thereof”, Proceedings of the IEEE, Volume: 80 , Issue: 1, Digital Object Identifier: 10.1109/5.119570, Publication Year: 1992, Page(s): 103 - 112
  4. ^ A. Mehta, D. Mirshekar-Syahkal and H. Nakano , “Beam adaptive single arm rectangular spiral antenna with switches”, Microwaves, Antennas and Propagation, IEE Proceedings - Volume: 153 , Issue: 1, Digital Object Identifier: 10.1049/ip-map:20050045, Publication Year: 2006 , Page(s): 13 – 18
  5. ^ Asad, M., Gilani, J., Khalid, A. and Iqbal, M.S., “Optimizing Q factor of square spiral antenna ”, PACCS 2010, Page(s): 227 - 230
  6. ^ Stephen E. Lipsky "Microwave Passive Direction Finding " SciTech Publishing, 2004 ISBN 1-891121-23-5 page 40

"Practical antenna" references[edit]

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